We are told that Adrianne bought a 9-foot leash for her dog. Let's imagine a situation where Adrianne holds the leash and does not move. Then the area where the dog can run is a circle with a radius of 9 feet.
We want to find the area of grass that the dog may run. To do so, we need to find the area of the circle. Recall that the area A of a circle equals the product of π and the square of its radius r.
A = π r^2
In this case, r= 9. Let's calculate the area using this information. We can use 3.14 for π.
